Backyard Aquaponics
A place to discuss aquaponics

http://www.google.com.au/search?q=yabbi ... 80&bih=843

And yes they are great to eat

Thanks gnash66,

I have been eating those things all of my life and never knew they were called yabbies. In New Orleans, La, USA where I am from they are called crayfish. I am going to have to do some research and learn to raise them here in Thailand

Yabbies are the Australian version. Much larger than our's here in the states.

I think this is what you want to look for:
กุ้งกุลาดำ
Goong La Dam.
Black Tiger Shrimp.
Was farmed very heavily in TL years ago.
I have had no luck in sourcing them, every time we go to a fish farm or government run research facility, we ask, they always say "Mai mee" or "Don't have"

Best I could do was some ornamental ones from the local market, both of which either escaped or were poached by some animal.

I would like to raise Black Tiger Shrimp too, but I hear it is difficult. I really like crayfish, yabbies, as they are very delicious. Are they hard to raise?

All of the above is dreaming at the moment. I have to get control of this fish pond and GB's first. I had 22 dead fish today. So far from the second stocking 12-7. of 320 fish I have lost 108. From the first stocking on 11-20 of 80 fish I have only lost 10. Just in the last day or two they seem to be eating better. So far I feel I got an unhealthy load of fish on the second stocking. I have some small, fat, gumpie type fish in there that my wife put in as expendables to test the water back in August. She put in 3 plus a few smaller ones. To date I must have a hundred and they swim and eat right along with the largest of the top teem.

Sorry to hear of further losses.
As you already know, I never found out why I lost so many baby fish, it gets disheartening at times.
I also blamed my first unintentional cull on sick fish.

Obviously you now know that you will need a lot more filtration as the fish grow, but I really don't think that is what's causing your deaths right now.

I don't know what else to suggest, I wish I could advise you further, but I'm all out of ideas.

As for keeping crayfish, mine seemed totally happy until they disappeared.
They also have unique characters too, which would make it hard to eat them.

I found myself talking to them when working on the system.
I didn't have a GF at the time, and really needed to get out more

I found myself talking to them when working on the system.
I didn't have a GF at the time, and really needed to get out more

LOL - I think when I was single I would rather have talked to the crawfish than a GF. They are a hell of a lot less trouble and expense and look what a GF got me - I am married and settled down (but super happy).

On the fish - out of 4oo stocked if 100 plus live and grown big and healthy I am in business at least from what I have learned so far about their breeding and reproducing. A few months from now I will probably be happy if some did die off. I ask this question before and it got lost some where in conversation - in my situation when and what size catfish (predators) should I buy to keep my system in check. I think two males should do it, but at what age to start with and when?

I think I would wait a while, then put some fingerling catfish in and see how you go.

Most of the farmers here only stock males, I read that a pregnant female can eat 60% more food to gain the same weight, it would be cheaper to go to the market and buy one !
If you're in it for the fish (with Tilapia) you really don't wan't females in the system.
It works out cheaper to buy male only fingerlings than the money you would waste on food in a pond that has too many babies, they reproduce like rabbits!

I know you're not fish farming as such, and probably the cost of the food doesn't bother you as the important thing is producing your own food, but I thought I'd mention it.

I copied my system from another fellow here in Thailand. He runs mixed tilapia and uses two male catfish as predators to control the population. His fish eat only algae. So mommy to be can eat all she wants. I have eaten fish from his pond and they taste great. The trick is to keep the balance between enough algae to feed the fish and at the same time keep the water clean enough that the fish stay healthy. I will probably also keep a few cats in another tank and feed them to eating size - using my trusty dip net I will supply them with fresh sushi when I have too many little ones. He trys to keep his fish tank with a 300 population and seems to be successful at doing so. His system has been up and running for about four years now. I will probably harvest about 20 adult size fish per month or 40 smaller just for my wife and I. We eat fish on average twice a day.

New problem - Referring to my previous post stating that I was going to put a stand pipe near the front of the bed and drain it out the present drain when I change over to a gravel bed will not work. At present my back row of GB's drain through the front row of beds into the FT. So if I put the stand pipe attached to a drain of a back bed it will have to run thru the bottom of the front bed and then out the 3/4 pipe to the FT. If I put a standpipe in the front bed I will block off the drainage of the back tank. So now I am thinking of having the GB's drain out at or near the top of the GB. From there the water can be piped through a new drain pipe to the FT. How would I do the plumbing? Any ideas or suggestions.

Why would that be a problem?
If I have visualised it correctly, all you have done is increase the level of the back bed before it overflows, which is exactly what you want to do.

The back bed is already elevated about 7 inches now. The water flows through the 3/4 inch pvc pipe in the front wall of the back bed near the bottom to the back side of the front bed. When the water in the front bed is deep enough (only an inch or two) the water then runs out the 3/4 inch pvc located in the front side of the front bed near the bottom and drains into the pond as shown in the photo. In both beds I have construction gravel about 6 inches deep and a mix of coco coir and rice hulls above. So I ask you, if I leave the coir/hull mix in the front bed and just change the back bed from the mix to gravel and make that one bed continuous flow, will I have any problem or will it all work fine? Then later when I change the front bed to continuous flow also, will I have too much water being drained at one time? Will the drain, 3/4 inch pvc be large enough to handle the drainage of two beds?

I think it should be fine to modify the back bed and let it flow through the front bed to the FT, I can't see any problems with that.

You have a large pond, so even 2 beds connected up won't take that much water out.
You can always put more water in once things are running, you do have to take into account a power failure and make sure the pond doesn't overflow if the pump goes off.

As for the 3/4 being able to handle the flow - That depends how much water you pump into it.
You will probably want to put a T-Piece on the pipe from the pump, one side of the T going the the GB the other going to a ball valve and possibly a spray bar going straight back to the pond.
This allows you to adjust the flow to the GB and aerate at the same time.

You will probably want to put a T-Piece on the pipe from the pump - this just a pvc T shaped piece?

one side of the T going the the GB the other going to a ball valve - what is a ball valve?

a spray bar going straight back to the pond - what is a spray bar?

How do you work it to regulate the flow of water?

Sorry for all of the dumb questions but I am new to plumbing. Thanks for all the help.

Yes.

The valves with a red bit on the top and a ball inside to regulate flow, you have one in the picture of the pond.


Basically a piece of pipe with lots of small holes in it, causes the water going back to the pond to be sprayed.


You open the valve to increase the flow, close it to decrease it